In Opera, you can do transactions in a private window. Make sure Opera's adblocker and tracking protection is turned on. Goto the URL opera://extensions and make sure no extensions are allowed to run in a private window except for maybe your password manager. If you goto the URL opera://settings/privacy, you'll see "protect me from malicious sites". That's like what Yandex does for its "protect from dangerous" sites feature.
Yandex itself does examine your downloads and sends bits of suspicious files to a server to be analyzed where it then flags the download and warns you. Opera doesn't have that. But, your anti-virus will scan downloads that Opera fetches.
Yandex does do strict verification of certificates in protected mode. But, I'm not sure what's involved in that exactly. Opera will warn you if something is wrong with a certificate and the connection though.
Yandex does have a Secure Wifi feature that runs your connection through some kind of encrypted tunnel/proxy/VPN through their servers to provide extra privacy on a public, unencrypted Wifi connection. This is in addition to the normal secure and encrypted https connection that should already be happening on a trusted site like a bank. Opera doesn't have this exactly, but you might gain some extra security turning on Opera's VPN when on public wifi. Or, for all programs, a system-wide VPN could be used.
So, Opera already has a lot of the things Yandex has. But, it might be nice to have the few missing features and have a Smartbox to control it all like Yandex has. I don't need it myself, but it wouldn't hurt.
I often listen to music in the sidebar panel but it is affected by all adblocks i've tried so far, so I come across many ads, and end up using just a normal page. how could I or anyone solve this? The side bar pages are not affected by any adblock
Currently most popular browsers and apps implemented "Dark mode" seamlessly without the need to restart the browser when the operating system switched the app theme to dark. With Opera as an exceptional case which I need to restart the Opera every day when my Windows app theme switched to dark mode because of sunset. To me, I think there should be an option to automatically switch like what other apps or browsers did. I knew some may not like the switch of theme automatically, that's why I suggest at least "light", "dark", "system default" these three options for color choosing. Here attached the current situation from other browsers developer version or similar version:
No option to choose, follow system by default, can install more themes
Firefox Alpenglow is a theme that change dynamically based on system color
Dark themes only
Can change theme with scheduled time and let user to choose which theme for both light theme and dark theme. I think it is the best option but it doesn't change their start page wallpaper with theme which the developers said they are working on that.
Hopefully, I can no longer manually restart Opera in the near future.